Year: 2026

Short answer: the TNP-FZ100 records normally in an A7 IV or an FX3, but “charging while shooting” will not rescue a long take — once the pack is in the bay its own Type-C port is completely covered, so any top-up runs through the body’s USB-C input, and whether that holds depends on the body and the supply wattage, not on the battery. What really caps recording time is body heat, not capacity. For two or three hours or more of continuous recording, neither swapping packs nor charging while shooting is a good trade; external power is the steadier answer. Below we separate the real limits of the three routes.

First, one thing to clear up: the port on the battery is unusable in-camera

The direct-charge port on the TNP-FZ100 sits on the side of the pack itself. Once the battery is seated in the bay, the wall covers it completely and there is no room to route a cable. So in practice “charging while shooting with a TNP-FZ100” has exactly one form: the pack powers the body as usual, while a cable runs from the camera’s USB-C port to a power bank or a PD supply.

That route only works if the body accepts USB power. The A7 IV, A7S III and FX3 all take PD over USB-C, and with a suitable supply the camera draws from the external source first, so the pack’s discharge slows markedly or stops altogether. Older bodies support USB charging but not USB power — with a cable attached they keep drawing from the battery, only more slowly. Check your camera’s manual on this point.

Three supply routes, and roughly how long each lasts

The table gives orders of magnitude for 4K at a normal bit rate, around 22°C ambient, a single camera and continuous recording. Actual time depends heavily on bit rate, frame rate, screen brightness and whether a fan is running.

The third route replaces the real pack with a dummy of the same shape, wired to an external supply or a USB power module. It removes capacity from the equation entirely, which suits fixed-position interviews, livestreams and conference recording. For the wiring details, see our dummy battery power guide.

The three real limits of charging while shooting

Limit one: is there enough power?

A recording body draws in the 5–10W range, and more at high bit rates, with stabilisation on and the screen bright. Feed it from an ordinary 5V/2A power bank and the input may only just match consumption or fall slightly short, so the pack keeps draining — you have moved from one hour to two, not to unlimited. A PD supply of 18W or more is what gives the charge a chance to actually hold.

Limit two: heat adds up

Charging produces heat and recording produces heat; do both at once and the interior warms faster than with either task alone. The A7 IV is fairly sensitive to temperature during long 4K takes, and recording while plugged in brings the overheat warning forward. The FX3 has an active fan and more headroom, but a blocked intake or a hot environment will still trigger protection.

Limit three: a cable changes how you shoot

Plugged in means the camera cannot move freely; handheld follow shots, gimbal work and quick repositioning all suffer. Many people conclude that carrying two more packs and rotating is preferable to living with a cable — which is the argument for a dual-slot case.

When to give up on charging while shooting

The test is simple. If a single take runs longer than the pack can supply and you cannot stop in between, do not count on charging while shooting — go to external power. Interviews, lecture capture, livestreams and multi-camera stage work all fall into that group.

Conversely, for documentary following, weddings and moving exterior work, the cable costs more than it gives. The right approach is three or four packs, all charged overnight in a dual-slot case, swapped between segments during the day. In that workflow the direct-charge port on the TNP-FZ100 earns its place: at lunch, any USB outlet will put half a charge back into the pack you have just pulled.

Video power on the FX3 and FX30 involves finer trade-offs. Our FX3 and FX30 video power guide compares the two bodies, including cooling design and recommended supply wattage.

A configuration that rarely goes wrong

1. Fixed main camera: dummy battery on a large external supply, with the pack as a buffer for power interruptions.
2. Moving work: TNP-FZ100 in the body, two spares in the bag, everything recharged at the end of the day.
3. Mixed situations: body USB-C on an 18W-plus PD bank, as an extender rather than a substitute for capacity.
4. Summer outdoors: keep the body out of direct sun, let it cool between takes, and never leave a plugged-in camera sealed in a bag.

What these have in common is that runtime is never bet on a single method. The battery buys mobility, the cable buys duration, and each covers its own stretch. More accessory combinations are listed in the TNP-FZ100 catalogue.

FAQ

Will the FX3 overheat recording 4K from a power bank?

It can, but it is more forgiving than a fanless body. The FX3 has active cooling and typically runs a long time at room temperature, provided the intake is not covered by a hand or a sticker. In direct summer sun, every body loses headroom.

Does charging while shooting cause swelling?

Not in normal use. Swelling is mostly tied to prolonged heat, failed overcharge protection or cell quality. Keeping the camera out of a sun-baked car and avoiding unknown chargers are the more effective precautions.

Will an ordinary power bank extend recording time on the A7 IV?

It will extend it, but by how much depends on the bank’s output. A 5V/2A output mostly just slows the decline; holding the level needs a PD fast-charge tier. Confirming that your bank supports PD output before you leave saves more weight than an extra battery.

Does swapping the battery mid-take lose the clip?

It ends the current clip. To change packs without stopping, you need external power to carry the camera, or a supply design that supports two batteries. That is why fixed-position work leans toward a dummy battery.

Short answer: yes. The TNP-FZ100’s rated energy is about 16.4Wh, far below the 100Wh cabin threshold, so it can travel with you on both domestic and international flights without airline approval. One hard rule still applies: spare lithium batteries go in carry-on only, never in checked baggage. The contacts also need protection against short circuits, and the quantity has to stay within what is reasonable for personal use. Below we separate the arithmetic, the energy bands and the practical security routine so you can tick them off before you leave.

Where 16.4Wh comes from

Aviation rules work in rated energy, in watt-hours, not in milliamp-hours. The formula is capacity times voltage divided by a thousand: 2280mAh × 7.2V ÷ 1000 ≈ 16.4Wh. That is the original NP-FZ100 rating, and the TNP-FZ100 is built to the same specification, so it lands in the same bracket.

The point is worth stressing because people often compare a 20,000mAh power bank with a 2,280mAh camera battery and conclude that the camera battery is “tiny, so obviously fine”. The conclusion is right but the reasoning is not: a power bank is rated at 3.7V cell capacity, so 20,000mAh comes to about 74Wh, still inside 100Wh; at 27,000mAh you are close to the ceiling. Convert to Wh before comparing and the milliamp-hour figure will not mislead you.

The three energy bands

The TNP-FZ100 falls in the first band, the least restricted category. Most carriers limit first-band spares to a quantity reasonable for personal use; IATA guidance is commonly twenty per passenger, individual carriers may be stricter, and their published rules take precedence. Five or six packs for a shoot rarely raises a question; a case of identical batteries invites one about what they are for.

Cabin or hold: the rule people get wrong

The distinction turns on the state of the battery. A pack installed in a camera, with the camera switched off and protected against accidental activation, can generally travel in checked baggage with the equipment. Spare packs carried separately must go in the cabin. The reason is that a short-circuit fire in the hold cannot be dealt with by the crew in time; in the cabin it can.

In practice, packing every battery into the checked suitcase is the common mistake. The correct split is one pack in the body, the rest in your carry-on bag, and power banks in the cabin as well. This holds for domestic and international flights alike, and virtually every carrier applies it.

Contact protection: what security is really looking at

The hazard in a lithium battery is the positive and negative terminals being bridged by metal at the same time. Loose in a bag with keys and coins is the textbook short circuit. Any one of three accepted measures will do.

• Keep the original packaging, one pack per slot — factory state is the safest.
• Tape over the metal contacts with insulating tape, or fit the supplied plastic cap.
• Put each pack in its own zip bag or battery case so they cannot touch.

A dual-slot charging case works too: the shell isolates the contacts and the closed lid doubles as storage, at the cost of a little more bulk than loose packs. For how these accessories are used, see our dual-slot case guide.

The practical order of operations at security

1. Before leaving, gather the batteries into one inner pocket of your carry-on rather than spreading them across three bags.
2. Confirm every pack is protected — original box, tape or a bag — with no exposed contacts.
3. If you are asked, say plainly that they are camera spares, and show the camera if it helps.
4. Do not put batteries in a metal case; metal reads as a muddle on the scanner and invites a hand search.
5. Once aboard, do not use a power bank to charge batteries; some carriers explicitly prohibit power bank use in flight.

Most of the time the X-ray shows a few neat rectangular blocks travelling with a camera, and the officer can identify them at a glance without further questions. What gets stopped is loose packs, unprotected packs and unusual quantities.

Edge cases that come up often

On a connection through a third country, local civil aviation rules apply. Most align with the standard, but a few regions are more sensitive about quantity, so on long multi-leg itineraries keep the count to four or fewer. International check-in desks occasionally ask to see the markings; a pack worn too smooth to read is easy to refuse, which is another argument for keeping the original packaging.

As for the battery’s own condition, capacity, temperature and swelling all matter. If the shell is visibly bulging before departure, do not board with it — that is a replacement signal. For more on judging battery condition and body compatibility, see the TNP-FZ100 section. If you are travelling with a full kit, the longer NP-FZ100 flight guide covers the rest.

FAQ

Will six TNP-FZ100 packs be stopped at security?

Usually not. Six come to roughly 98Wh in total, still within personal use, provided they are split across your carry-on and the contacts are protected. If you are carrying a dozen or more, it is worth preparing a commission letter or an itinerary in case you are asked.

Can batteries go in checked luggage?

Spares cannot. A pack installed in a device that is switched off and protected against activation is accepted by most carriers. When in doubt, keep it in the cabin — that choice is never wrong.

The shell is scuffed and the ratings are unreadable — can I still take it?

There is a risk of refusal. Security needs to verify rated energy and may decline carriage when the marking cannot be read. Replace the pack with one that has an intact shell, or keep the original packaging as evidence of the specification.

Can I bring a power bank and camera batteries together?

Yes. Both are managed as spare lithium batteries and both travel in the cabin. The difference is that a power bank must keep a legible capacity marking and is usually banned from use in flight; camera batteries have no in-use restriction but still cannot be checked.